Stander Symposium abstract book - University of Dayton
Stander Symposium abstract book - University of Dayton
Stander Symposium abstract book - University of Dayton
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POSTER SESSION 1<br />
The bab Locus Model for Synergistic Gene Regulatory Interactions in Development and<br />
Evolution.<br />
Presenter(s): Eric M Camino, Kaitlyn R Francis, Jordan E Vellky<br />
Advisor(s): Thomas M Williams<br />
Biology - Graduate Research<br />
Complex spatial and temporal patterns <strong>of</strong> gene expression (production <strong>of</strong> a gene’s encoded protein) are crucial to animal development and changes<br />
in expression patterns are a common mode <strong>of</strong> evolutionary innovation. Thus, understanding development requires answering: (1) what are the<br />
DNA elements, so called CREs, controlling expression, (2) how the DNA sequences <strong>of</strong> CREs encode gene regulatory capabilities, (3) whether and<br />
how CREs work together to make complex expression patterns, and (4) how CRE sequences identify their gene target(s) <strong>of</strong> regulation in a 3-dimensional<br />
nucleus? These answers will aid studies to reveal the mechanisms <strong>of</strong> gene expression, and thus animal, evolution. A model to address these<br />
questions is the bab locus <strong>of</strong> fruit flies. This locus contains the duplicate bab1 and bab2 genes that shape a derived pattern <strong>of</strong> pigmentation in the<br />
species Drosophila melanogaster. The relevant bab expression pattern is controlled by two CREs which we found to interact in a non-additive, or<br />
synergistic, way to yield this pattern. Ongoing studies seek to trace: when and how CRE synergism evolved, which CRE sequences encode their<br />
synergistic activity, how these CREs interact with the bab genes, and whether synergism is limited to these genes. Ultimately, this work aims to<br />
connect how animal form is programmed into 1-dimensional DNA sequence and how this program evolves.<br />
The Effects <strong>of</strong> Silver Nanoparticles on Mouse Embryonic Cell Renewal and Cell Cycle<br />
Presenter(s): Christopher J Stucke<br />
Advisor(s): Yiling Hong<br />
Biology - Honors Thesis<br />
The use <strong>of</strong> silver nanoparticles in commercially made products is rapidly increasing, and there is no regulation on the disposal <strong>of</strong> these nanoparticles.<br />
As human exposure to silver nanoparticles rises, this study determines the effects <strong>of</strong> this exposure on stem cell factor gene expression and<br />
stem cell fate. This was accomplished by introducing varying concentrations <strong>of</strong> silver nanoparticles into mouse embryonic stem cells for varying<br />
amounts <strong>of</strong> time. Western blot and immunoprecipitation techniques were run on these cells to determine how the responses <strong>of</strong> stem cell factors<br />
Oct4, Nanog, P53, SirT1, and Rb differ from their normal function within the cell. In addition, this study also determines whether programmed<br />
cell death is occurring in response to the silver nanoparticle treatment. The results <strong>of</strong> the research provided necessary scientific data to improve or<br />
eliminate potential toxicity <strong>of</strong> nanoparticles, and information for relevant authority when approving products for consumer uses.<br />
The mutations, molecular mechanisms, and constraints directing the evolution <strong>of</strong> a<br />
Drosophila cis-regulatory element<br />
Presenter(s): William A Rogers, Joseph R Salomone, David J Tacy<br />
Advisor(s): Thomas M Williams<br />
Biology - Graduate Research<br />
A major goal <strong>of</strong> evolutionary developmental biology research is to illuminate how evolution acts on development to cause phenotypic change. A<br />
wealth <strong>of</strong> data implicates changes in gene expression as the predominant means by which morphological traits evolve, and likely via mutations in<br />
cis-regulatory elements (CREs) that specify gene expression patterns. Each expression pattern is encoded in a CRE as a regulatory logic comprised<br />
<strong>of</strong> a collection and organization <strong>of</strong> binding sites for certain transcription factor (TF) proteins. While several case studies have identified instances<br />
<strong>of</strong> CRE evolution, how encoded regulatory logics evolve remains poorly understood. An intraspecific comparison <strong>of</strong> Drosophila melanogaster sexually<br />
dimorphic abdominal pigmentation patterns presents an opportune situation to reveal how regulatory logics evolve. The degree <strong>of</strong> female<br />
pigmentation varies between populations and this variation stems from genetic variation at the bric-a-brac (bab) locus, which encodes the Bab TF<br />
proteins that act as repressors <strong>of</strong> pigmentation development. Bab expression in females is controlled by a CRE known as the dimorphic element.<br />
We identified four dimorphic element alleles that possess different gene regulatory capabilities. By determining the sequence and function <strong>of</strong> the<br />
CRE possessed by the most recent common ancestor <strong>of</strong> these extant populations we were able demonstrate how few mutations were necessary<br />
and sufficient to alter the function <strong>of</strong> the derived alleles. Ongoing studies seek to reveal how these few mutations <strong>of</strong> a relatively large effect modify<br />
an ancestral regulatory logic.<br />
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